Screw-jack head



No. 6l0,045. Patented Aug. 30, I398. D. GLENN.

SCREW JACK HEAD.

(Application filed Apr. 8, 1898.)

(No Model.)

WITNESSES A TTOHN cu, womu'mq. wasumcrou, D. c.

5o socket is provided with a groove g, adapted DANIEL GLENN, OF DEL RIO, TEXAS.

SCREW-JACK HEAD.

- SPECIFICATION forming part of Letters Patent No. 610,045, dated August 30, 1898.

Application filed April 8, 1898. Serial No. 676,862. (No model.)

To all whom it may concern.-

Be it known that I, DANIEL GLENN, of Del Rio, in the county of Val Verde and State of Texas, have invented a new and Improved Screw-Jack Head, of which the following is a full, clear, and exact description.

My invention relates to an improvement in screw-jack beads by which the same are provided with ball-bearings and the parts so locked together that they cannot separate, the locking mechanism being used also as a brake to prevent the jack from running backward.

The invention consists of the novel features of construction which will be hereinafter described and claimed.

Reference is to be had to the accompanying drawings, forminga part of this specification, in which similar characters of reference indicate corresponding parts in all the figures.

Figure 1 is an elevation of a jack with the head in section. Fig. 2 is a section taken upon the line 2 2 of Fig. 1, and Fig. 3 is an enlarged detail section on the line 3 3 in Fig. 2.

The device is applicable to screw-jacks, but may be applied to any other form of jack or to similar mechanism in which a shaft revolves and is to be locked to a stationary head. The jack, as herein shown, is mounted upon a frame A, which may be of any suitable construction. Upon the upper end of said frame is mounted a nut 0, through which operates the threaded shaft 13. As herein shown the nut is provided with ball-bearings D, the balls lying between the faces of the thread on the nut and shaft. This, however, forms no part of my present invention.

At the upper end of the shaft is a fixed head E, which may be an integral part of the shaft or secured thereto. The upper portion of this head is provided with a peripheral groove 6, and the upper surface of the head is provided with a circular groove adapted to receive the balls L, which form a bearing be tween the fixed head E and the rotatable head G. The head G-is provided on its under surface with a recess or socket adapted to embrace the upper end of the head E, and

the inner surface of the side wall of this to register with the groove 6 when the two parts are placed in position.

Within the groove 9 is placed a set of locking-blocks F, made as segments of a ring and fitting snugly in the groove. The depth of the groove 9 in the rotatable head is such as to permit of the blocks F being entirely received in said groove, so that the head G- may be removed'fromthe head E. The blocks F are forced inward by means of a series of setscrews H, which pass through the flange at the lower end of the head G. These screws force the blocks F into the groove e in the head E, and thus lock the two parts E and G together, while permitting rotation of one upon the other. One of these blocks, as the block F, is engaged by a special set-screw H, which has a head extending outside the head G, so that it may be engaged bya wrench. By setting this screw up tighter than ordinarily the block F may be forced into the groove 6, so as to prevent rotation of the two heads upon each other. This block F"wi1l thus act as a brake to prevent the jack from running down. The head G is preferably provided with a rounded or hemispherical upper end, upon which is placed a cap I, having a socket fitting over the rounded end of the head, and a flat upper surface. This cap is secured in place by set-screwsql, which pass through the lower edge of the cap and enter a slot g'inthe upper portion of the head G. The slot 9 is of such width that the set-screws J will only partially fill the same, and thus permit of the rocking of the cap upon the head.

Having thus fully described my invention,

I claim as new and desire to secure by Letters Patent A screw-jack, having a threaded shaft terminating at one end in a peripherally-grooved head, a bearing-head recessed to fit over said 

